The goal of our research is to obtain an atomistic understanding of the elementary steps of surface reactions. We want to learn how and why the atoms and molecules on a surface move making such mystic things like surface catalysed chemistry happen, or how to make them move such that structures of nanometer scale can be produced. Such knowledge is the basis for a thorough understanding of heterogeneous catalysis and for new methods in materials processing. We use lasers to drive these reactions and laser spectroscopy to study the outcome.